Method of and apparatus for controlling air flow in pneumatic systems



July 7. 1931. M. 1.. EMERSON 1,813,487

METHOD OF AND APPARATUS FOR CONTROLLING AIR FLOW IN PNEUMATIC, SYSTEMS Filed Oct. 18, 1928 3 Sheets-Sheet l az'iaedmwzz r July 7. 1931. M. L. EMERSON 1,813,487-

METHOD OF AND APPARATUS FOR CONTROLLING AIR FLOW IN PNEUMATIC SYSTEMS Filed Oct. 18, 1928 v 3 Sheets-Sheet 2 35 I 1 33 a9. /7 33 )F 3 I P I l I J3 \fl I Lffifi I II I /Z l I'L N we /5" r a 0 126. M 2 g n 21 July 7. 1931.

M. L. EMERSON 1,813,487

METHOD OF AND APPARATUS FOR CONTROLLING AIR FLOW IN PNEUMATIC SYSTEMS 3 Sheets-Sheet 3 Filed Oct. 18, 1928 ii I p:

Patented July 7, 1931 UNITED STATES PATENT OFFICE I KEBTON L. EMERSON, E SYRACUSE, YORK.,.ASSIGNOR T0 THE LAMSON COMPANY,

' 0F SYRACUSE, NEW YORK, .A. GORPORATION 0F MASSACHUSETTS to an improved method of and means for IETHOD OF AND APPARATUS FOR GONTMLLING AIR FLOW IN PNEUMATIC" SYSTEMS Application filed October 18, 1928. Serial No. 313,249.

This invention pertains to pneumatic despatch systems and relates more particularly controlling the air flow in such a system. Much effort has been expended in designing so-called power control apparatus for shutting off the flow of air, either by closing a valve or stopping the fan motor when the tube line is empty so that power will not ill be wasted. Since it is undesirable to parallel the pneumatic tube line with cables, conduits, electric wires, or the like for actuating the power control means, and since it has commonly been thought necessary to shut off the air flow whenever the last carrier emerged from the tube, either at the clerks (sending) station or at the central (cashiers) station, resort has been had to apparatus of the so-called minimum flow type wherein the entry of a carrier into the tube at either end produces a pressurevariation in the tube operative to start the full air flow, and wherein discharge of the carrier at either end of the tube results in cessation of carrier impelling flow through change in pressure or velocity of the air in the tube incident to such discharge. While the minimum flow type of control is practical and widely used, it is very delicate in its construction and inits response to pressure variations, and requires frequent adjustment to keep it in satisfactory operation, particularly when the power control apparatus is installed in situations where it is exposed to dust and dirt.

Careful study of the situation has convinced me that while it may be desirable from a theoretical standpoint to cut off the-- air flow whenever the tube line is empty (as by the discharge of a carrier at the cashiers' as well as the clerks station) this not by any means necessary to economical operation as a practical matter. At. the cashiers or central station the operation of making change, authorizing charge accounts, etc, takes but a veryshort time, usuallyless than a minute, so that the interval between discharge of the carrier from the delivery terminal and the introduction into the despatch terminal for return to the clerks station is of comparatively short duration, and results in but little waste of power, it being remembered that during the transit of the carrier from and to the clerks station, power is necessarily expended in any system, and that even inthe minimum flow type of apparatus there is a continuous flow of air, amounting to a substantial percentage of the full. flow, in the intervalsbetween transits of carriers.

on the other hand, the intervals between the despatch of carriers from the clerks station are often of considerable duration, taking place in some installations or in. certain store departments not oftener on the average than once an hour. Thus it means he provided at the cl'erks station only for wholly cutting 01f the air flow in the intervals between successive transactions, results closely'approximating those secured from usual power control apparatus (so far as economy and power is concerned) may readily be obtained. 1

In accordance with. the present invention, the air flow through the tube line is maintained at its full value from the time the carrier is despatched until its return to the sending station. and is then wholly cut oif. Conceivably, the carrier impelling flow may be initiated and stopped by the use of a manually actuated valve or switch at the sending station, but suchan arrangement to be effective in the saving of power would require the attention of the clerk until the return of the carrier. son, I prefer to provide automatic means at the clerks or sending station for starting and stopping the air flow. For this purpose. I preferably take advantage of the fact that a predetermined complement of carriers is normally assigned to each sending station, each carrier when despatched, returning to its point of origin, and provide. control means responsive to the presence of an idle carrier in or its absence from a predetermined position at the sending station so that whenever a carrier is absent from the control means (as for example during its despatch to the central station and its return) the full carrier impelling air flow is maintained in the tube line, but that whenever there is a full complement of carriers at the sending station, the control means, responding to the presence of the carriers, cuts off the air flow completely. Preferably the control means responds to the weight of the carrier, although I contemplate other forms of control as within the scope of the invention. The apparatus herein disclosed is of simple character as compared with most power control devices; it is relatively cheap to con struct and install; it is positive in action and requires but little attention for repairs or adjustment, and under most conditions of installation results in a saving of .power equivalent to, if not greater than, that obtained by theuse of the much more expensive and troublesome systems heretofore employed.

In the accompanying drawings I have illustrated by way of example one desirable embodiment of the invention, it being understood that various changes in the shape, size and proportion of parts, and the substitution of equivalents may be made with out departing from the spirit of the invention.

In the drawings: a Fig. 1 is a diagrammatic elevation tosmall scale, showing the invention embod ed in a normal type of pneumatic tube line;

Fig. 2 1s a side elevation of the lmproved terminal apparatus arranged for downward discharge of carriers, the parts being shown in inoperative position with the controlling valve closed;

Fig. 3 is a view similar to Fig. 2 but showing the controlling valve open;

Fig. 1 is a front elevation of the apparatus shown in Figs. 2 and 3, omitting the controlling valve and adjacent parts of the tube; A o V Fig. 5 is a vertical section to largerscale substantially on the line 55 of Fig. 4;

Fig. 6 is a fragmentary bottom plan view, partly in section substantially on the line 66 of Fig. 5; V l

Fig. 7 is a side elevation showing terminal apparatus similar to that of Fig. 2 but arranged for upward discharge of-carriers; and

Fig. 8 is a section to larger scale substan tially on the line 88 of Fig. 7,.showin g details of a desirable form of closure for a carrier despatch opening.

Referring to the drawings and particu larly to Fig. 1, I have indicated diagrammatically a pneumatic tube 1 leading from the clerks or sending station 2 to the central of cashiers station 3. At the cashiers stationothis tube is connected in usualv manner to means for producing carr1er mpellingi t b 21 l ading from the casing 22, is a nipair flow in the line, such for example as a pump or the vacuum tank 1. The tube 1 is above and below the box.

at its front side, or sides, with an opening 9 '(Fig. 5') through which carriers may beinserted and removed. This opening is normally closed by means of a door 10, hinged at 11, and provided with a handle 12. A spring 18, or an equivalent weight, tends to swing the door to closed position, and during the transmission of carriers through the pneumatic line the door is held firmly closed in airtight engagement with the edges of theopening by atmospheric pressure acting upon its outer side. Any suitable packing material, for example a strip let of felt, or rubber, may be interposed be tween the door and the wall of the casing to ensure an air-tight joint.

Arranged vertically in the rear part of thebox is a substantially vertical tubular guide 15 secured firmly in position bysolder or other suitable connection, and projecting The lower projecting portion 15 of the tubular guide is adapted to be connected to the tube 6 leading from the cashiers station by means of a sleeve 16 or other appropriate connecting element. In the arrangements shown in Figs- 2, 3 and 5 the upper end portion 15 of the tubular guide which projects outsideof the box 8, is closed by means of an airtight cap 17 The front part of the tubular guide 15.

is cut away within the box as shown at 18 to provide an elongate opening through which carriers arriving through the tube may discharge into the interior of the box. I-preferably provide deflector means 19, 19 against the rear wall of the tube 15 adapted to cause carriers moving e-itherupwardly or downwardly along the guide 15 to be diverted forwardly into the front of the box 8.

-Within the box 8 I provide a false bottom 20 spaced from the bottom proper of the box and which preferably inclines downwardly and forwardly toward the lower part of the opening 9. This false bottom 20 is provided with an opening 20 of sufiicient size to permit the ready passage of carriers therethrough. Registering with this opening is the upper end of a tube 21 which leads downwardly through the bottom of the box Sinto a casing 22. Directly in line with the ple 23 adapted to be connected by means of a sleeve24 or other appropriate device .to the tube 1 leading to the cashiers station. The casing 22 is connected to or integral with a hollow part 25' providing a valve chamber within which is mounted a valve 26, here shown as of butterfly type, secured to a shaft 27, one end of which projects outwardly through the wall of the valve chamber. The upper part of the valve chamber is connected by means of a short pipe or nipple 28 to the interior of the box 8, the nipple28 entering the bottom of the box 8 at a point near the edge of the false bottom 20. Av guard member 20 extends from the lower part of opening 18 in the tube 15 to the rear edge of the false bottom 20, such guard member being so designed as to prevent entry of a carrier beneath the false bottom while permitting free flow of air from the tube 15 to the nipple 28.

A lever 29 is fixedly secured to the end of the shaft 27 and at one end this lever is slotted for the reception of a pin projecting from the lower end of a rod 30 arranged to move vertically in guides as for example, a vertical bore in a boss 31 (Fig. 4) projecting from the box and a socket in a boss 32 in the upper part of the box. The rod 30' constitutes part of a rack comprising a series of cradle-like members 33, 33, 33 etc. each of said cradle-like members being adapted to support a carrier, C, C G etc. The lever 29 is provided with an adjustable weight 34 which is normally adjusted so as to overbalance the weight o-f the rod 30, the'rack carried thereby, and a series of carriers filling all but one of the cradles 33 so that the parts tend to assume the position shown in 3 with the valve 26 open. However, the adjustment of the weight is'such that when all of the cradles contain carriers, the

' weight 34 is overbalanced and the parts oovalve 34 being connected to the door 10 cupy the position shown in Fig. 2 with the valve 26 closed.

Preferably I provide a cover 34 normally closing the entrance 2() to the tube 21, the

b means of a link 35 pivotally attached to lug 36 projecting from the inside of the door so that when the door 10 is swung down to the dotted line position, Fig. 5, the

cover 34 simultaneously opens so as to expose the entrance to the tube 21.

Near the rear end of the false bottomv 20 I provide a transverse shaft 37 mounted in 1 brackets or other supports, and on this shaft I mount a swinging detector member 38. A spring 39 coiled about the shaft 37 tends to'hold the detector 38 in the upper position indicated in Fig. 5. A rod 40, project-- ing rigidly downwardly from the detector 38 through an opening in the false bottom 20, engages an arm 41 (Fig. 6). of a lever device pivoted to swing-on a pin 42 projecting downwardly from the false bottom 20. This lever device has an arm 43 disposed closely adjacent to the inner surface of the box 8 and carrying a valve pad 44 normally closing an aperture 45 in the wall of the box. Registering with this opening, at the outside of the box, is a whistle device 46 of such character that when the aperture 45 s open the suction or low pressure within the box will cause the whistle to sound.

In the modified arrangement shown in Figs. 7 and 8, the box, with its appurtenances including the valve and carrier supporting rack, is identical with that shown in the preceding figure, but in this instance it is arranged for use with an upwardly extending despatoh tube. For the purpose, the lower end 15 of the tubular guide 15 is closed by means of a cap 17 while its upper end is open and connected by means of the sleeve 16" to the upwardly extending tube 6 leading from the cashiers station. Likewise a cap 22 shown in Fig. 3 as closing an aperture in casing 22 is removed to permit attachment to the casing 22 of the lower end of the despatch tube 1 leading to the cashiers station, the lower end of the nipple 23 being closed by a cap 22 In this instance the despatch tube 1" is furnished with an opening 46" for admission of a carrier, and this opening is normally closed by means of a door 47 mounted upon a sprin hinge at 48 which tends to keep the door closed, the door being provided with a handle 49. Any suitable packing means, if necessary, may be provided to ensure a tight joint between the door and the walls of the tube.

The arrangements disclosed in Figs. 1 to 6 inclusive operate substantially as follows, it being assumed that the parts normally occupy the position shown in Fig. 2 a full complement of carriers in the rack, the valve 26 and the door 10 being closed. henthe clerk wishes to have a transaction performed at the central or cashiers station, he removes one of the carriers,

from the rack, and in the usual manner inserts in the carrier the currency, charge order, or other material to be transmitted to the distant station. In removing the carrier from the rack, the total weight of the rack is decreased suihciently to permit the weight 34 to raise the rack with the remaining carriers, at the same time opening the valve 26 and thus permitting full carrier impelling flow of air to enter the end 7 of the tube 6 and flow through the latter tube to the box, and thence through the nipple 28 past the open valve 26 and through the valve casing 22 into the pipe 1.

The operator now opens the door 10, simultaneously opening the cover 34 and. exposing the open upper end of thetube 21. The carrier is now inserted in the tube 21 and drops by gravity through the casing 1 with 13 101" 4 example the uppermost carrier G, 2)

22 and the nipple 23 into the pipe 1 where it is swept onwardly by the air current and carried to the cashiers station. As soon as the carrier has been inserted in the tube 21, the door is closed, thus closing the opening leading into the tube 21, but wlthout aflecting the flow of air current since the air is free to pass through the guard 2O into the valve casing 22. .Vhen the proper transaction has been performed at the cashiers station, the carrier is inserted in the open end '7 of the tube 6 and is impelled by the flowing air current through the latter tube to the clerks station where it enters the box upwardly through the tubular guide and is diverted by the deflector 19 toward the forward part of the box, where it falls upon the deflector member 38. The weight of the carrier depresses the deflector member and through the pin swings the lever arm i3 so as to remove the pad 4% from the opening 45. At this time the sucion is stiil maintained within the box and thus air is drawn inwardly through the whistle 4:6, causing the latter to sound, thus notifying the clerk that a carrier has arrived in the box. The clerk now opens the door 10 and removes the carrier, thus permitting the deflector 38 to resume its noral position, whereupon the whistle ceases to sound. The clerk removes the contents from the carrier and places it in the proper cradle of the rack causing the rack to descend, thus raising the weight 8 closing. the valve 26, and restoring the parts to normal position wherein flow of air through the tube line is completely out off.

In describing the above sequence of operations it is assumed that but a. single carrier is removed from the rack at one time, but if more than one carrier be removed and transmitted to the cashiers station it is obvious that the valve 26 will remain ooen until all of the carriers which have been despatched have been returned and replaced in the rack.

The apparatus thus provides automatic means for completely cutting off air flow in the tube line leading to any given sending station, whenever such tube line is idle that is to say when all of the carriers assigned to such station are idle and in readiness at the station for use. On the other hand, the apparatus automatically opens the valve to permit carrier impelling air flow whenever a carrier is put into use and maintains a full air flow until such time as the carrier or carriers have returned to the sending station.

The arrangements shown in Figs. 7 and S operate in substantially the same way as that above described except that in des patching a carrier to the door 47 is opened and the carrier placed within the upwardly extending tube 1 leading to the cashicrs station. When this door is closed the air current admitted through the open valve passes through the casing 22 and intothe tube 1*, thus driving the carrier forward to the cashiers station. When the carrier is returned it is received through the pipe or tube 6 and passes downwardly into the box, being deflected by the member 19 toward the forward part of the box so that it comes to rest on the deflector 38 and operates the signal as above described.

Nhile a whistle forms a desirable form of signal, it is obvious that other types of signal, for example electrically actuated lamps, bells, etc. may be employed. It is further contemplated that various changes in the shape, arrangement, and function of parts and the substitution of equivalents fall within the scope of the invention.

I claim:

1. Power control apparatus for use with a pneumatic tube line extending between two stations, said apparatus comprising a substantially air-tight box having a normally closed door, and connections secured tofthe box adapting it to form a receiving terminal alternatively for upwardly or downwardly extending pneumatic tubes.

2. Power control apparatus for use with a pneumatic tube line extending between two stations,said apparatus comprising a substantially air-tight box having a normally closed aperture in its front wall, a tubular guide extending through the box and having portions projecting from both the top and bottom of the box and adapted respectively for connection alternatively to downwardly or upwardly extending delivery tubes, and means for closing the inactive end of said tubular guide, the forward side of said guide having an elongate opening for delivery of carriers into the box.

3. Power control apparatus for use with a pneumatic tube line extending between two stations, said apparatus comprising a box having a normally closed aperture in its wall, a tubular guide extending from a point outside of the box to the inside thereof, said guide forming the terminal of a delivery tube, one side of the guide having an elongate opening within the box, and a deflector for directing carriers arriving through said. opening toward the aperture in the box wall.

4. Power control apparatus for use with a pneumatic tube-line extending between two stations, said apparatus comprising a box having an opening in its front wall, adoor normally closing said opening, a vertical tubular guide disposed in the rear part of the box, said guide having an elongate opening within the box and tubular portions extending outwardly beyond the top and'bottom walls respectively of the box, means uniting one of said outwardly extending portions of the guide to a delivery tube,

means closing the other end of the guide, and deflector means within the guide for directing carriers outwardly through the elongate opening therein toward the door of the box.

5. Power control apparatus for use with a pneumatic tube line extending between two stations, said apparatus, comprising a box so connected to the delivery tube of the line as to receive carriers delivered therefrom, a detector within the box adapted to be held in abnormal position by a carrier in the box, a normally closed valve, connections for opening the valve when the detector is in abnormal position, and a whistle whihch sounds when the valve is open.

6. Power control apparatus for use with a pneumatic tube line extending between two stations, said apparatus comprising a box, tubular conduits connecting the interior of the box with the delivery and despatch tubes respectively of the pneumatic tube line, a movable cover normally closing the inlet to the conduit leading to the despatch tube, and means for opening the cover to admit a carrler.

7. Power control apparatus for use with a pneumatic tube line extending between two stations, said apparatus comprising a box having an opening in its wall, a door normally closing the opening, tubular conduits connecting the interior of the box with the delivery and despatch tubes respectively of the pneumatic tube line, a movable cover normally closing the inlet to the conduit leading to the despatch tube, and means so connecting the cover to the door of the box as to open the cover when the door is opened.

8. Power control apparatus for use with a pneumatic tube line extending between two stations, said apparatus comprising a box havin an oaenin in its wall a door normally closing the opening, tubular conduits connecting the interior of the box with the delivery and despatch tubes respectively of the pneumatic tube line, a movable cover normally closing the inlet to the conduit leading to the despatch tube, and means so connecting the cover to the door of the box as to open the cover when the door is opened, means providing a passage for air from the interior of the box to the despatch tube, and a valve controlling the flow of air through said passage.

9. Power control apparatus for use with a pneumatic tube line extending between two stations, said apparatus comprising a box having an opening in its wall, a door normally closing the opening, tubular conduits connecting the interior of the box with the delivery and despatch tubes respective ly of the pneumatic tube line, a movable cover normally closing the inlet to the conduit leading to the despatch tube, means so connecting the cover to the door or the box asto open the cover when the door is opened, arcasing having a valve chamber and valve therein, means connecting the valve chamber with the interior of the box and with the despatch" tubev respectively, and guard means preventing passage .of carriers from the box into the valve chamber. [.10. Power control apparatus for use with a pnuematic tube line extending between two stations, having anyopening in its wall, a door. normally closing the opening, tubular conduits connecting the interior of the box with the delivery and despatch tubes respectively .of the pneumatic tube'line, a movable cover normally closing the inlet to the conduit leading to the despatch tube, means so connecting the cover to the door of the boxas to open the cover when the door is opened, a casing having a valve chamber and a valve therein, means connecting the valve chamber with the interior of the box and with the despatch vtfube'respectively, means tending to open the valve, and means responsive to the presence of a predetermined number of carriers in a predetermined position for holding the valve closed.

11. A terminal for a pneumatic despatch system comprising a housing providing a substantially air-tight chamber, a door in the housing giving access to the chamber, and pneumatic tubes leading to and from the chamber, one of said tubes extending substantially vertically through the chamber and having an opening in its side wall through which a carrier passes from the tube to the chamber, the other tube opening into the chamber near the bottom of the latter, the chamber constituting a portion of the air circuit through the system.

12. Power control apparatus for use with a pneumatic tube line extending between two stations said apparatus comprising a box having an opening in its wall, a door normally closing the opening, tubular conduits connecting the interior of the box with the delivery and despatch tubes respectively of the pneumatic tube line, a false bottom in said box having an opening, through which carriers may pass, and which registerswith the upper end of the conduit to the despatch tube, means normally preventing the passage of a carrier through the opening, and a connection between the preventing means and the door whereby the means is rendered inoperative when the door is opened.

13. Power control apparatus for use with a pneumatic tube line extending between two stations said apparatus comprising a box having an opening in its wall, a door normally closing the opening, tubular conduits connecting the interior of the box with the delivery and despatch tubes respective ly of the pneumatic tube line, a false botsaid apparatus comprising a box 1 tom in said box having an opening, through which carriers may pass, and which registers with the upper end of the conduit to the despatch tube, and means connected to the door and normally preventing the passage of a carrier through the opening into the conduit.

14:. Power control apparatus for use with a pneumatic tube line extending between two stations, said apparatus comprising a box having an opening in its wall, a door normally closing the opening, tubular conduits connecting the interior of the box with the delivery and despatch tubes respectively of the pneumatic tube line, and guard means connected to the door and normally obstructing the inlet to the conduit leading to the despatch tube whereby to prevent accidental redespatch of arriving carriers, said guard means being so associated with the door as no longer to obstruct the inlet when the door is opened.

Signed by me at Syracuse, New York this 2d day of October 1928.

MERTON L. EMERSON. 

